Need For Speed Underground Rivals Codes -

Boss cars:
Some race events are listed as "Boss Race" in the event description. Win that event under the gold difficulty setting to be awarded that Boss's car (1969 Dodge Charger, Subaru Impreza WRX STi, Chevrolet Corvette Z06 and Nissan Skyline R34 GTR). When you win a Boss car, it will appear in the Pocket Garage, and you can race it in any game event.

Bonus parts:
Complete the last race of a set with a gold medal.

Car list:
The following cars are unlocked for purchase in order.

Volkswagen Golf GTI 2.0L: $22,000 
Ford Focus ZX3: $18,000 
Mazda Miata MX-5: $19,000 
Dodge Neon: $17,000 
Nissan Sentra SE-R SPEC-V: $21,000 
Toyota Celica GT-S: $23,000 
Nissan 240SX: $30,000 
Mitsubishi Eclipse GSX: $32,000 
Mazda RX-7: $34,000 
Mazda RX-8: $48,000 
Pontiac GTO: $46,000 
Subaru WRX STi: $46,000 
1969 Dodge Charger: $44,000 
Toyota Supra: $52,000 
Nissan 350Z: $54,000 
Mitsubishi Lancer: $51,000 
Ford SVT Mustang Cobra R: $56,000 
1967 Ford Mustang: $65,000 
Nissan Skyline R34 GTR: $70,000 
Chevrolet Corvette Z06: $72,000